T6 Yes I understand what You're saying but You're not booting KDE4... You are booting KDE4 LiveCD with the legacy kernel which is suppose to run with Pentium MMX CPU's BUT Youre breaking x before it gets to the KDE4. You're logging into the FailSafe session which does not requires 500 MB ram and allows to install PCLinuxOS iso to hdd. Now going from there. After installation Youre going to the FailSafe session again and You can setup network / upgrade / remove KDE4 / install other DE.
Its not DE that is the problem. Its the fact that Pentium MMX is not compatible with any kernel but legacy one which ought to work with such a prehistoric device

.
The only 2010 iso that came out with legacy kernel is the iso made by Texstar for Linuxera as far as I know. I have seen the link to it on the forum long time ago and I remember downloading it. It worked fine till I ran into the zlib1 problem and reinstalled with the genuine MiniMe 2010 iso.
I am not sure if I am right. Heck I could be wrong and I wouldn't be surprised

but if I were BPSoftware nothing (beside the lack of the iso link

) would stop me from trying it

!
Oh and about the inability to boot from livecd... I could do that with my old Pentium MMX mobo... but there is always a way out:
1) Check does the latest bios version can change that and if yes flash it...
2) If flashing BIOS does not help... Move the HDD to a newer puter... remove the original HDD. Install the LiveCD to the HDD and move it back to the old machine... I mean its not windows... There should be no BSOD coz of the GPU drivers...
BUT bare in mind that if You are not skilled enough and Your knowledge of PCs is not sufficient You may end up with two borked puters software-wise in best case and hardware-wise in worse...If You dont know what You're doing... Don't do it till You do know what You're doing or (if You have a syndrom of "I just had to try it!" like myself) start experimenting. Experiments MAY and probably WILL go wrong... You have been warned. I take no responsibility for borked machines
.Andy